摘要
本文采用以热传导为主的旋转电加热筒干燥莲子,考察了不同干燥温度(60、70、80、90℃)、不同转速(0.5、1、1.5 r/min)下莲子转筒传导干燥特征和干莲子全粉糊化特性。结果表明,莲子转筒干燥过程一直处于降速干燥段;干燥温度显著影响莲子转筒干燥过程(p≤0.05),试验转速对干燥过程无显著影响(p>0.05)。莲子转筒干燥过程可以用Cavalcanti-Mata模型准确模拟(R^(2)>0.999,E%<5.00%,RMSE<0.01);干燥有效扩散系数在3.94×10^(-10)~1.00×10^(-9) m^(2)/s之间,并随着干燥温度的升高而增大。莲子转筒干燥过程显著影响莲子全粉糊化特性。转筒干燥温度升高,莲子全粉峰值粘度、最终粘度均出现显著降低趋势(p≤0.05)。60℃转筒干燥莲子全粉的峰值粘度、最终粘度分别为1676.33、2228.00 cP;90℃转筒干燥后,其值分别为1268.00、1909.33 cP。60℃转筒干燥莲子表面疏松、多孔,90℃转筒干燥莲子因淀粉凝胶化,表面结构致密,微观结构发生改变。相比热风烘箱穿流干燥,莲子转筒传导干燥降低了干燥不均匀度(最大值为4.59%),有利于均匀干燥。本研究为确定莲子高品质转筒干燥工艺以及干莲子粉后续加工过程提供了技术支持。
To determine the characteristic behaviors of lotus seeds during drying and assess the quality of the flour produced from dried lotus seeds using a rotary dryer,lotus seeds with an initial moisture content of ≈63% to 10% wet basis(w.b.)were dried at controlled temperatures of 60,70,80,and 90℃ with rotational speeds of 0.5,1,and 1.5 r/min.The adhesive properties of the lotus seed flour were investigated using a rapid visco-analyzer(RVA).The results indicate that the drying process is prolonged by rotary drying.No constant-rate drying phase was found.Strong influences of temperature on the drying process were evident(p≤0.05).By contrast,rotational speed did not significantly affect the drying process(p>0.05).Estimates predicted using the Cavalcanti-Mata model were in good agreement with the experimental results(R^(2)>0.999,E%<5.00%,RMSE<0.01).The effective moisture diffusivity of lotus seeds was between 3.94×10^(-10) and 1.00×10^(-9) m^(2)/s.This increases as drying temperature increased from 60 to 90℃.The drying process considerably affects the adhesive properties of the flour obtained.Peak and final viscosities were significantly lower when the lotus seeds were dried at higher drying temperatures.The corresponding values at 60℃ were 1676.33 cP and 2228.00 cP,respectively.Those at 90℃ were 1268.00 cP and 1909.33 cP,respectively.The results suggest that lotus seed microstructures change with drying temperature due to starch gelatinization during rotary drying.The surfaces of lotus seeds dried at 60℃ are more porous,while more densely packed structures are noted in lotus seeds dried at 90℃.Lotus seed surfaces are denser if they are dried at higher temperatures because of changes in their microstructures.Compared to oven drying,rotary drying produces lotus seeds with more uniform moisture content,and a maximum variability in moisture content of only 4.59%.This study may aid in development of high-efficiency and high-quality lotus seed drying techniques and applications of lotus seed flour within the food industry.
作者
徐建国
徐刚
石劲松
张森旺
顾震
刘云飞
XU Jian-guo;XU Gang;SHI Jin-song;ZHANG Sen-wang;GU Zhen;LIU Yun-fei(Institute of Applied Chemistry,Jiangxi Academy of Sciences,Nanchang 330096,China)
出处
《现代食品科技》
CAS
北大核心
2021年第6期184-192,共9页
Modern Food Science and Technology
基金
江西省重点研发计划项目(20181BBF68011)
江西省科学院科技计划项目(2018-YZD2-19、2020-YZD-1)。
关键词
干燥
莲子
转筒干燥
热传导
糊化特性
凝胶化
干燥不均匀度
drying
lotus seeds
rotary drying
thermal conduction
adhesive properties
gelatinization
moisture non-uniformity
作者简介
徐建国(1979-),男,副研究员,研究方向:干燥技术与设备研究;通讯作者:刘云飞(1989-),男,博士,助理研究员,研究方向:农产品加工研究。
